Comparison between an elastic-perfectly plastic finite element model and a purely elastic analytical model for a spherical indenter on a layered substrate

1997 ◽  
Vol 300 (1-2) ◽  
pp. 177-188 ◽  
Author(s):  
K.C. Tang ◽  
A. Faulkner ◽  
N. Schwarzer ◽  
R.D. Arnell ◽  
F. Richter
1985 ◽  
Vol 52 (1) ◽  
pp. 67-74 ◽  
Author(s):  
V. Bhargava ◽  
G. T. Hahn ◽  
C. A. Rubin

This paper describes a two-dimensional (plane strain) elastic-plastic finite element model of rolling contact that embodies the elastic-perfectly plastic, cycle and amplitude-independent material of the Merwin and Johnson theory, but is rigorous with respect to equilibrium and continuity requirements. The rolling contact is simulated by translating a semielliptical pressure distribution. Both Hertzian and modified Hertzian pressure distributions are used to estimate the effect of plasticity on contact width and the continuity of the indentor-indentation interface. The model is tested for its ability to reproduce various features of the elastic-plastic indentation problem and the stress and strain states of single rolling contacts. This paper compares the results derived from the finite element analysis of a single, frictionless rolling contact at p0/k = 5 with those obtained from the Merwin and Johnson analysis. The finite element calculations validate basic assumptions made by Merwin and Johnson and are consistent with the development of “forward” flow. However, the comparison also reveals significant differences in the distribution of residual stress and strain components after a single contact cycle.


1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.


2014 ◽  
Vol 6 (1) ◽  
pp. 19-25
Author(s):  
Gergely Máté Kiss ◽  
István Vajda

Abstract Co-simulation is a method which makes it possible to study the electric machine and its drive at once, as one system. By taking into account the actual inverter voltage waveforms in a finite element model instead of using only the fundamental, we are able to study the electrical machine's behavior in more realistic scenario. The recent increase in the use of variable speed drives justifies the research on such simulation techniques. In this paper we present the co-simulation of an inverter fed permanent magnet synchronous machine. The modelling method employs an analytical variable speed drive model and a finite element electrical machine model. By linking the analytical variable speed drive model together with a finite element model the complex simulation model enables the investigation of the electrical machine during actual operation. The methods are coupled via the results. This means that output of the finite element model serves as an input to the analytical model, and the output of the analytical model provides the input of the finite element model for a different simulation, thus enabling the finite element simulation of an inverter fed machine. The resulting speed and torque characteristics from the analytical model and the finite element model show a good agreement. The experiences with the co-simulation technique encourage further research and effort to improve the method.


1985 ◽  
Vol 52 (1) ◽  
pp. 75-82 ◽  
Author(s):  
V. Bhargava ◽  
G. T. Hahn ◽  
C. A. Rubin

This paper presents finite element analyses of two-dimensional (plane strain), elastic-plastic, repeated, frictionless rolling contact. The analysis employs the elastic-perfectly plastic, cycle and strain-amplitude-independent material used in the Merwin and Johnson analysis but avoids several assumptions made by these workers. Repeated rolling contacts are simulated by multiple translations of a semielliptical Hertzian pressure distribution. Results at p0/k = 3.5, 4.35, and 5.0 are compared to the Merwin and Johnson prediction. Shakedown is observed at p0/k = 3.5, but the comparisons reveal significant differences in the amount and distribution of residual shear strain and forward flow at p0/k = 4.35 and p0/k = 5.0. The peak incremental, shear strain per cycle for steady state is five times the value calculated by Merwin and Johnson, and the plastic strain cycle is highly nonsymmetric.


2016 ◽  
Vol 858 ◽  
pp. 913-916 ◽  
Author(s):  
Konstantinos Zekentes ◽  
Konstantin Vassilevski ◽  
Antonis Stavrinidis ◽  
George Konstantinidis ◽  
Maria Kayambaki ◽  
...  

Purely vertical 4H-SiC JFETs have been modeled by using three different approaches: the analytical model, the finite element model and the compact model. The results of the modeling have been compared with experimental results on a series of fabricated self-aligned devices with two different channel lengths (0.3 and 1.1μm) and various channel widths (1.5, 2, 2.5, 3, 4 and 5 μm). For all the considered models I-V and C-V characteristics could be satisfactorily simulated.


2019 ◽  
Vol 48 (3) ◽  
pp. 168-187
Author(s):  
Sunish Vadakkeveetil ◽  
Arash Nouri ◽  
Saied Taheri

ABSTRACT Being able to estimate tire/rubber friction is very important to tire engineers, materials developers, and pavement engineers. This is because of the need for estimating forces generated at the contact, optimizing tire and vehicle performance, and estimating tire wear. Efficient models for contact area and interfacial separation are key for accurate prediction of friction coefficient. Based on the contact mechanics and surface roughness, various models were developed that can predict real area of contact and penetration depth/interfacial separation. In the present work, we intend to compare the analytical contact mechanics models using experimental results and numerical analysis. Nano-indentation experiments are performed on the rubber compound to obtain penetration depth data. A finite element model of a rubber block in contact with a rough surface was developed and validated using the nano-indentation experimental data. Results for different operating conditions obtained from the developed finite element model are compared with analytical model results, and further model improvements are discussed.


2014 ◽  
Vol 1659 ◽  
pp. 55-61
Author(s):  
Ryan M. Pocratsky ◽  
Maarten P. de Boer

ABSTRACTFixed-fixed beams are ubiquitous MEMS structures that are integral components for sensors and actuation mechanisms. However, residual stress inherent in surface micromachining can affect the mechanical behavior of fixed-fixed structures, and even can cause buckling. A self-tensioning support post design that utilizes the compressive residual stress of trapped sacrificial oxide to control the stress state passively and locally in a fixed-fixed beam is proposed and detailed. The thickness and length of the trapped oxide affects the amount of stress in the beam. With this design, compression can be reduced or even converted into tension. An analytical model and a 3D finite element model are presented. The analytical model shows relatively good agreement with a 3D finite element model, indicating that it can be used for design purposes. A series of fixed-fixed beams were fabricated to demonstrate that the tensioning support post causes a reduction in buckling amplitude, even pulling the beam into tension. Phase shifting interferometry deflection measurements were used to confirm the trends observed from the models. Controlling residual stress allows longer fixed-fixed beams to be fabricated without buckling, which can improve the performance range of sensors. This technique can also enable local stress control, which is important for sensors.


2018 ◽  
Vol 85 (6) ◽  
Author(s):  
Simon P. H. Skovsgaard ◽  
Henrik Myhre Jensen

Failure by steady-state kink band propagation in layered materials is analyzed using three substantially different models. A finite element model and an analytical model are developed and used together with a previously introduced constitutive model. A novel methodology for simulating an infinite kink band is used for the finite element model using periodic boundary conditions on a skewed mesh. The developed analytical model results in a transcendental equation for the steady-state kink band propagation state. The three models are mutually in good agreement and results obtained using the models correlate well with the previous experimental findings.


1999 ◽  
Vol 121 (3) ◽  
pp. 374-380 ◽  
Author(s):  
Jack E. Helms ◽  
Chihdar Yang ◽  
Su-Seng Pang

A model of a taper-taper adhesive-bonded joint under cylindrical bending has been derived using first-order laminated plate theory. Shear correction factors were used to account for transverse shear deformation. A FORTRAN program was written to integrate the resulting system of twelve simultaneous, linear, first-order, differential equations with variable coefficients. The Linear Shooting Method was used to solve the model. A finite element model was developed using the COSMOS/M commercial finite element package to verify the analytical model for a cross-ply laminate. The analytical model results agreed well with the finite element models and predicted peak adhesive stresses within about 2% of the finite element model.


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